Circulating Air Oven

ABSTRACT

The invention relates to a circulating gas oven incorporating a cooking surface wherein the cooking surface and air above are heated by a circulating gas system involving ducting and gas diffusers. The oven is portable and the cooking surface is made of ceramic or glass material. The ducting means and diffusers are adapted to create a laminar air flow. Foodstuff such as pizza can be cooked in a uniform manner.

CROSS REFERENCES TO RELATED APPLICATIONS

This application claims priority to international application number PCT/GB2010/001610 filed on Aug. 26, 2010 which claims priority to GB patent application number 0915075.6 filed on Sep. 1, 2009, the entire disclosures of which are hereby incorporated by reference.

TECHNICAL FIELD

This invention relates to a circulating gas oven which also incorporates a cooking surface wherein the cooking surface and air above are heated by a circulating gas system involving ducting and gas diffusers.

BACKGROUND ART

Usually ovens operate by the principle of having means to heat air in the oven which in turn heats the enclosed foodstuff. In certain cases, such as for pizza it is necessary to have a modified oven whereby the foodstuff is cooked from below by a cooking means and also from above by hot air. This was the essence of the invention in U.S. Pat. No. 5,413,033 (19 May 1995)—033, which disclosed a cooking surface with its own heating means so that the heated air also heated the cooking surface. This necessarily means that the cooking surface is not going to be heated by a direct forced current of hot air and thus the heating of the cooking surface is likely to be prone to less control and poorer heating. This problem was overcome in part in U.S. Pat. No. 5,605,092 (25 Feb. 1997)—092, where it was suggested that in addition to the disclosure in 033 a further heating means could be employed to heat the cooking surface. However in neither 033 or 092 was there disclosed the use of any circulating air system so as to heat the cooking surface and provide heat from above the said cooking surface. In U.S. Pat. No. 6,640,695 (4 Nov. 2003) a means of heating a cooking surface is disclosed but no means is disclosed whereby the air heating the cooking surface is thence ducted over the cooking surface and then to exhaust. Further although an enclosed chamber is disclosed it does not serve to circulate the hot air over the top of the cooking surface. US 2006/0191528 (31 Aug. 2006) discloses a device for placing over a hot air source but no cooking surface or air circulation is disclosed.

US 2008/0135037 (12 Jun. 2008)—037 discloses a heated air system where the heated air heats a cooking surface from below and then heat from above is provided by a combination of (1) heating air and (2) radiation from an air heated element where that air heats the element by means of suitable port. It is also necessary for the heating effect below to be of a degree greater than the heating from above. 037 requires differential heating effects wherein the lower heating effect is of a magnitude greater then the upper and that there be specialised means for providing radiative heat transfer from above by, specifically, a transition port where a first pass is required before entry into the port and thereafter second heating effects via radiative heat transfer.

US 2009/0064985 (12 Mar. 2009) discloses a heated air system but fails to provide for direct heating of the cooking surface by heated air via the gas diffuser but instead provides for direct heating only by a stream of heated air flowing over the cooking surface and radiative heating from a heated ceramic platen from above. U.S. Pat. No. 4,800,865 (31 Jan. 2989) discloses a cooking device whereby a cooking surface is heated directly by a stream of hot air and some of the hot air is ducted to heating the surface of the cooking surface with any excess air being ducted to exhaust before it encounters the cooking surface. This has the disadvantage that useful heated air is vented to exhaust and the remainder is diffused, possibly turbulently over the cooking surface. This configuration is undoubtedly going to adversely affect the performance of the oven.

SUMMARY OF INVENTION

In order to cook certain types of foodstuff such as pizza there is a need to achieve oven conditions whereby the foodstuff is cooked from a base as well as by reason of the heat of air above it. Usually the base temperature is lower than the temperature of the air above it and the effect is that the base can cook the foodstuff from below and the air above can cook the foodstuff from above but at differing rates and using a heat source from which the oven can be detached.

According to one aspect of the preset invention there is provided a single base member or platen which is positioned away from heat radiation means; such means being heated by a flow of hot gas, which gas then flows over the cooking surface to exhaust. Preferably such radiation means can also operate as a gas diffuser. Once the gas has heated the radiation means and has also flowed past the platen it can then be ducted so as to flow over another part of the platen and ultimately to exhaust. In on embodiment further vents may be employed to bring cooler, ambient, air into the vicinity of the platen so that it can operate at a lower temperature.

The heated gas, usually air or air plus burner products can be generated by a variety of means such as a gas or electric ring, a heated hob or a barbeque. Further the platen may be a pan, sheet or tray of variable thickness made from a variety of refractory, metallic or other heat resistant materials. Likewise the gas diffuser must be made of a material, preferably metallic which is sufficient to withstand high temperatures and will also be a good radiator of heat when heated.

In order to ensure that the substance on the platen is subjected to a uniform level of heat it is preferable to ensure that the hot gas flowing over the platen surface and after it has heated the first aspect of the platen flows in a laminar manner since eddying will cause the temperature distribution to be less uniform.

BRIEF DESCRIPTION OF THE DRAWING

A specific embodiment of the invention will now be described, by way of example. There is a single FIGURE (FIG. 1) showing the preferred embodiment in exploded view.

DETAILED DESCRIPTION OF THE DRAWING

A specific embodiment of the invention is shown in FIG. 1. The apparatus may be made from standard readily available components but should be chosen to withstand temperatures in the region of 400 C.

The Platen (3) is housed between the Chassis (2) and Gas Diffuser And Lower Ducts (4) which are secured together to form a single unit and wherein the diameter of the Platen (3) and Gas Diffuser And Lower Ducts (4) are approximately the same but where the Chassis (2) is of a greater diameter so as to allow the Main Ducts (6) to be subject to the entry of hot gas from below. The Top Ducting Housing (1) is designed such that it can capture the hot gas emerging from the Main Ducts (6) and vent it to flow over the Platen (3) to Exhaust (7).

Preferably the Gas diffuser And Lower Ducts (4) are shaped to as to allow smooth flow of any gas from below such that it flows around the sides of the Gas Diffuser and Lower Ducts (4) and up towards the Ducts (6).

In one embodiment Side Vents (5) may be incorporated so as to enable ducts to be built to provide additional cooling to the space between the Platen (3) and the Gas Diffuser And Lower Ducts (4) if additional cooling of the Platen (3) is required.

Embodiments of the invention provide some or all of the following features:

I. A circulating gas oven incorporating radiative heat transfer elements which comprise no more than one platen, circulating gas diffusion means and ducting means characterised in that:

A. the platen is heated as to one aspect by direct or indirect heat transfer from the gas diffusion means,

B. thereafter the circulating gas is ducted, via ducting means to heat another aspect of the platen and any object placed thereon wherein such heating is controlled by further ducting means and

C. the circulating gas is then exhausted.

II. Apparatus as set out above wherein the oven is portable.

III. Apparatus as set out above wherein the further ducting means are adapted such that the subsequent flow of vented gas through those said means is substantially laminar.

IV. Apparatus as set out above wherein the flow of circulating gas interacting with the diffuser is substantially laminar.

V. Apparatus as set out in paragraphs I or II wherein the flows of circulating gas interacting with the diffuser and after venting through the further ducting means is substantially laminar.

VI. Apparatus as set out above wherein the platen is made of a ceramic or glass material.

VII. Apparatus as set out above wherein the circulating gas entering into the further ducting means includes at or about the point of entry a gas flow splitter.

VIII. Apparatus as set out in paragraph VII above wherein the said gas flow splitter is adapted such that one stream of gas performs the purpose of directly heating the platen and the other stream of gas performs the purpose of indirectly heating the platen.

IX. Apparatus as set out above wherein the platen is subjected to an additional gas flow from venting means which are separate from and independent to the circulating gas and ducting means.

X. Apparatus as set out in any of paragraphs I to VIII above wherein the platen is subjected to an additional gas flow from venting means which, before being subjected to the platen, are separate from and independent to the circulating gas and ducting means but which thereafter are free to be mixed with the circulating gas.

XI. Apparatus as set out in paragraph X above wherein the additional gas flow is generated by entrainment means and wherein such entrainment arises by a Venturi effect driven by the flow of any proximate and flowing gas.

XII. Apparatus as set out above wherein the gas diffuser comprises two plates in any configuration.

XIII. Apparatus as set out above wherein the vents from the ducting means and the place of exhaust are substantially diametrically opposed.

XIV. Apparatus as set out in any of paragraphs I to XII wherein the vents from the ducting means and the place of exhaust are substantially diametrically opposed.

XV. Apparatus as set out above wherein there is incorporated a door such that the door may be used to allow for access to the platen.

XVI. Apparatus as set out above wherein the Platen and any other feature with which it is incorporated is stepless so as to enable items to be placed upon the platen by sliding.

XVII. Apparatus as set out above wherein the gas flows may be regulated by any means.

XVIII. Apparatus as set out above wherein the said apparatus is adapted for use with a heat source derived from solid fuel.

XIX. Apparatus as set out above wherein the said apparatus is adapted for outdoor use. 

1-19. (canceled)
 20. A gas oven for providing a circulation of heated gas to a gas exhaust, the gas oven comprising: a platen, a first region below the platen containing a diffuser, a second region above the platen containing the gas exhaust, and one or more first ducts between the first region and the second region; wherein: the diffuser is adapted to deflect gas received in the first region towards the first ducts, and the diffuser has a radiative surface facing the platen to radiate heat towards the platen; the first ducts are disposed apart from the gas exhaust and an upper part of the second region is adapted such that gas received through the first ducts passes across an upper surface of the platen; wherein the first and second region, the gas inlet, the gas exhaust, the diffuser and the first ducts are disposed to promote laminar flow in the circulation of gas at least over the upper surface of the platen.
 21. A gas oven as claimed in claim 1, wherein the first and second region, the gas inlet, the gas exhaust, the diffuser and the first ducts are disposed to promote laminar flow in the circulation of gas substantially throughout the gas oven.
 22. A gas oven as claimed in claim 1, wherein the platen is made of a ceramic material.
 23. A gas oven as claimed in claim 1, wherein the platen is made of a silicate material.
 24. A gas oven as claimed in claim 1 wherein the diffuser comprises two plates.
 25. A gas oven as claimed in claim 1 wherein the first ducts and the gas exhaust are substantially diametrically opposed across the platen.
 26. A gas oven as claimed in claim 1 wherein the platen is stepless so as to enable food products to be slid directly on to the platen.
 27. A gas oven as claimed in claim 1 adapted to be portable.
 28. A gas oven as claimed in claim 1 wherein an interior cavity is provided between the diffuser and the platen.
 29. A gas oven as claimed in claim 9, wherein the interior cavity comprises at least one vent.
 30. A gas oven as claimed in claim 10, wherein said at least one vent opens externally to the gas oven.
 31. A gas oven as claimed in claim 10, wherein said at least one vent opens internally to the gas oven.
 32. A gas oven as claimed in claim 1 wherein the gas oven is adapted for mounting over a source of heated gas.
 33. A gas oven as claimed in claim 13 adapted for use with a source of heated gas comprising a solid fuel burner.
 34. A gas oven as claimed in claim 1 adapted for outdoor use.
 35. A method of heating a food product in an oven with a circulation of heated gas, the oven comprising a platen, a first region below the platen containing a diffuser, a second region above the platen containing a gas exhaust, and one or more first ducts between the first region and the second region; wherein the circulation comprises: admission of heated gas into the first region; deflection of the heated gas by the diffuser to the first ducts, whereby the heated gas heats the diffuser and the diffuser radiates heat to a lower surface of the platen; passage of the heated gas through the first ducts from the first region to the second region; and passage of the heated gas from the first ducts to the gas exhaust by means of an upper part of the second region across an upper surface of the platen with substantially laminar flow.
 36. A method of heating a food product as claimed in claim 16 wherein the circulation of gas substantially throughout the oven is with substantially laminar flow.
 37. A method of heating a food product as claimed in claim 16 comprising heating gas with a solid fuel burner.
 38. A gas oven for mounting on a source of heated gas provided by a solid fuel burner providing a circulation of heated gas to a gas exhaust, the gas oven comprising: a platen, a chassis below the platen for mounting on a solid fuel burner and containing a diffuser, a housing above the platen containing the gas exhaust, and one or more first ducts between the chassis and the housing; wherein: the diffuser is adapted to deflect gas received from the solid fuel burner towards the first ducts, and the diffuser has a radiative surface facing the platen to radiate heat towards the platen; the first ducts are disposed apart from the gas exhaust and an upper part of the housing is adapted such that gas received through the first ducts passes across an upper surface of the platen; wherein the chassis, the housing, the gas inlet, the gas exhaust, the diffuser and the first ducts are disposed to promote laminar flow in the circulation of gas at least over the upper surface of the platen. 